Police on Monday arrested Philip Markoff, 22, of Quincy, in the woman's death last week at a luxury hotel. Markoff is to be arraigned this morning in Boston Municipal Court on charges of murder and unlawful possession of a firearm.

Markoff's father is a Syracuse dentist, the Daily News reported.

But police believe Markoff may have been involved in other crimes against women who also posted ads on Craigslist.

"There may be other victims out there, and if you are, we want you to come forward," Suffolk District Attorney Daniel Conley said. "Our top priority is holding Philip Markoff accountable. He's a predator."

Markoff is charged with killing Julissa Brisman, 26, who was found dead April 14 at the Boston Marriott Copley Place. The New York City woman advertised massage services on Craigslist and had a massage table set up in the room where she was shot Tuesday, police said.

In addition, Markoff is charged with kidnapping and armed robbery in a separate case involving another woman he met on Craigslist.

Conley said evidence from computer forensic experts and "old-fashioned shoe leather" linked Markoff to the two crimes. The man police say is Markoff was seen on video surveillance using a hand-held texting device at several of the hotels.

But Markoff's fiancee says police have the wrong man and there is no way he could have done it.

In an e-mail to ABC's "Good Morning America, Megan McAllister said Philip Markoff "could not hurt a fly." She called him "a beautiful person inside and out," according to the message read on the air today.

McAllister said she and Markoff expect to be married in August "and share a wonderful, meaningful life together."

Police said they had long suspected that Brisman's killer was connected to a robbery at the Westin Copley Hotel in Boston.

Authorities believe Markoff also may be connected to the attempted robbery Thursday in Warwick, R.I., of an exotic dancer who had posted an ad on Craigslist. She was held at gunpoint before her husband entered the room and her attacker fled.

Boston police are working with Warwick authorities in that case, Davis said.

Markoff, a Boston University graduate student, was arrested by Boston police after he was stopped south of Boston on Interstate 95 in Walpole, Police Commissioner Ed Davis said at a news conference.

Authorities said Markoff is originally from Upstate New York and lives in Quincy, just south of Boston. A Facebook profile matching Markoff's identity, including his photograph, lists him as a 2007 graduate of State University of New York-Albany and in the 2011 class at BU.

A Boston University spokeswoman told Boston radio station WBZ-AM that Markoff had been suspended from the medical school after his arrest.

Conley said police hope more possible victims who advertised on Craigslist come forward so authorities can build a stronger case against Markoff. "If you are" a victim, said Conley, "we want to help you."

"He has no criminal record," said Davis, who added that the suspect is from upstate New York. "We are very, very happy to have this off the street in such a timely way."

Davis would not comment if a weapon has been recovered but said more details on the investigation will be made public at the arraignment. Authorities have also obtained a warrant to search Markoff's home, police said.

Boston police said they've also received more than 150 tips about Brisman's killing.